科研之友
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摘要
This paper is the last in a series related to pozzolanically stabilizing dredged material (DM) using up to 20 different combinations of lime, cement kiln dust (CKD), fly ash (FA), Portland cement (PC), and slag cement. The fine-grained nature of the DM and the presence of high sulfate concentrations (0.6-3.25% by weight) in the stabilized dredged material (SDM) blends derived from the raw materials themselves posed concern for potential ettringite formation and swell. The sulfate contents of the SDM blends were well in excess of the National Lime Association%26apos;s thresholds for mitigating against swell (%26lt; 0.8% by weight SO4). The quantitative mineralogical results showed that the lime and lime/FA SDM blends showed moderate to high ettringite formation (1.6-4.6% by weight) up to 6 months of curing, with all available sulfate bound to ettringite. The lime and lime/FA SDM blends consistently maintained the highest pHs through 6 months, which caused continued release of alumina and increases in strength. The CKD and CKD/FA SDM blends showed the highest ettringite contents through 28 days of curing (up to 5%), but with little additional formation of ettringite through 6 months of curing. The total sulfate content of the SDM blends was not a good predictor of ettringite formation potential, because of decreases in pH below the ettringite stability threshold and, even more importantly, the apparent limited availability of soluble alumina in the SDM blends. Swell tests performed on six SDM blends showed slight consolidation, and no ettringite was detected in the two specimens that swelled. DOI: 10.1061/(ASCE)GT.1943-5606.0000584.
- 出版日期2012-3
